200 watts to kWh per day and month

4.80 kWh/day

for 200 W running 24/7 · 144 kWh/month · $23.76/month at 16.5¢

200 W by hours of use

Use	Per day	Per month	Cost/month
1 h/day	0.20 kWh	6.0 kWh	$0.99
2 h/day	0.40 kWh	12.0 kWh	$1.98
4 h/day	0.80 kWh	24.0 kWh	$3.96
8 h/day	1.60 kWh	48.0 kWh	$7.92
12 h/day	2.40 kWh	72.0 kWh	$11.88
24 h/day	4.80 kWh	144.0 kWh	$23.76

kWh = W × hours ÷ 1000. Devices with thermostats or compressors cycle, so actual use is often lower than the rated wattage × hours.

4.80 kWh running 24 hours, 1.60 kWh at 8 hours.